<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .a {
            margin-top: 20px;
            background-color: aqua;
        }
        .b {
            margin-top: 10px;
            background-color: aquamarine;
        }
        .p {

        }
    </style>
</head>
<body>
    <div class="a">
        <div class="b">
            <p class="c"></p>
        </div>
    </div>
</body>
</html>